I cannot figure out this equation, solving for x.
4^2x - 4^x - 20 = 0
Can someone help?
Thanks,
Stefan
note that this is $\displaystyle (4^x)^2 - (4^x) - 20 = 0$
let $\displaystyle 4^x = y$, then you have
$\displaystyle y^2 - y - 20 = 0$
this is just a quadratic equation, hopefully you can solve it for $\displaystyle y$. when done, replace $\displaystyle y$ with $\displaystyle 4^x$ and solve for $\displaystyle x$ by using the logarihm to the base 4